In recent years there has been great interest in the design of practical asymmetric syntheses of vitamin E. Consequently much effort has been expended to find more economical routes to produce natural vitamin E. (See for example, H. G. W. Leuenberger, W. Boguth, R. Barner, M. Schmid, R. Zell, Helv. Chim. Acta, 62, 455, 1979; N. Cohen, W. F. Eichel, R. J. Lopresti, C. Neukom, G. Saucy, J. Org. Chem., 41, 3505, 1976.) These studies are directed to methods for preparing, from optically-active intermediates of microbial origin, the isoprenoid side chain of vitamin E or .alpha.-tocopherol, because it is extremely difficult to introduce the two designated (*) chiral centers via chemical methods. For example, a four carbon chiral synthon (2) derived from (S)-.beta.-hydroxyisobutyric acid and a five carbon chiral synthon (3) prepared via yeast reduction were incorporated into the side chain of .alpha.-tocopherol. Both 2 and 3 were prepared using oxidative and reductive processes of microbes. ##STR1##